Stent retrieval system

ABSTRACT

A braided stent having a plurality of retrieval and/or repositioning levers includes a stent body formed of a plurality of wires interbraided in a braided pattern. The repositioning and/or retrieval levers have a loop portion extending radially away from the stent body and first and second legs extending along the stent body. The levers are configured to be actuated radially inward toward the central longitudinal axis of the stent by a radially inwardly directed force to radially collapse the stent.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/338,044, filed on May 18, 2016, the disclosureof which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to devices, methods and systems forretrieval and/or repositioning of an implanted stent. More particularly,the present invention relates to implantable stents having stentretrieval levers for easy retrieval and/or repositioning of theimplanted stent.

BACKGROUND

An intraluminal prosthesis is a medical device used in the treatment ofdiseased bodily lumens. One type of intraluminal prosthesis used in therepair and/or treatment of diseases in various body vessels is a stent.A stent is a generally longitudinal tubular device formed ofbiocompatible material which is useful to open and support variouslumens in the body. For example, stents may be used in the vascularsystem, urogenital tract, gastrointestinal tract, esophageal tract,tracheal/bronchial tubes and bile duct, as well as in a variety of otherapplications in the body.

Stents generally include an open flexible configuration. Thisconfiguration allows the stent to be inserted through curved bodylumens. Furthermore, this configuration allows the stent to beconfigured in a radially compressed state for intraluminal delivery.Once properly positioned adjacent the target location in the body lumen,the stent is radially expanded so as to support and reinforce the bodylumen. Radial expansion of the stent may be accomplished by inflation ofa balloon attached to the delivery device or the stent may be of theself-expanding variety which will automatically radially expand onceunconstrained by the delivery device.

Various techniques or systems have been proposed for retrieving and/orrepositioning an implanted stent. For example, some stents may include aretrieval suture or wire located at one end of the stent. The retrievalsuture or wire may be engaged by a retrieval tool, and, upon twisting oraxially pulling retrieval suture or wire, the stent is contractedthereby allowing retrieval of the stent.

Prior retrieval systems often require certain user-sensitive techniques,such as twisting or turning in order to reposition or remove the stent.Moreover, the retrieval suture or wire that allows the stent to pursedown or reduce in diameter generally results in a reduction in diameterover a relatively short distance from the end of the stent that theretrieval suture or wire is located and does not cause the stent to bereduced in diameter along a majority of the length of the stent. Theremoval of the stent is then reliant on an extraction force sufficientto overcome the frictional resistance between the stent and the intimalwall of the body lumen.

Accordingly, there is an ongoing need to provide alternativerepositioning and/or retrieval mechanisms for an intraluminalprosthesis, such as a stent.

SUMMARY

The present disclosure is directed to various embodiments of a stent,for example a braided stent, having an integral repositioning and/orretrieval mechanism.

In a first example, a stent includes a tubular body formed of one ormore interwoven wires. The tubular body has a lumen extendingtherethrough from a first open end of the tubular body to a second openend of the tubular body. The tubular body has a length measured from thefirst open end to the second open end and a longitudinal axis extendingtherebetween. The stent further includes a plurality of repositioningand/or retrieval levers spaced apart circumferentially around the firstopen end and extending beyond the first open end. The repositioningand/or retrieval levers extend radially outward from the tubular body.Each repositioning and/or retrieval lever has first and second legsextending along a portion of the tubular body toward the second openend. The repositioning and/or retrieval levers are configured totranslate a radially inward squeezing force applied to the repositioningand/or retrieval levers at a location beyond the first open end to aradially inward contracting force along the first and second legsextending along the tubular body.

Alternatively or additionally, in another example, the plurality ofrepositioning and/or retrieval levers are separate elements from theinterwoven wires forming the tubular body.

Alternatively or additionally, in another example, the plurality ofrepositioning and/or retrieval levers include three levers attached toand extending beyond the first open end of the tubular body.

Alternatively or additionally, in another example, each of the pluralityof repositioning and/or retrieval levers extends radially outward fromthe tubular body at an angle of between 20 and 90 degrees from thelongitudinal axis.

Alternatively or additionally, in another example, each of the pluralityof repositioning and/or retrieval levers extends at an angle of between30 and 70 degrees from the longitudinal axis.

Alternatively or additionally, in another example, the plurality ofrepositioning and/or retrieval levers are made of a material having agreater stiffness than a material of the one or more interwoven wiresforming the tubular body.

Alternatively or additionally, in another example, the first and secondlegs of each of the repositioning and/or retrieval levers extend over25% or more of the length of the tubular body.

Alternatively or additionally, in another example, the first and secondlegs of each of the repositioning and/or retrieval levers extendsubstantially over the entire length of the tubular body from the firstopen end to the second open end.

Alternatively or additionally, in another example, each of the first andsecond legs of each of the repositioning and/or retrieval levers extendshelically along an interwoven wire forming the tubular body.

Alternatively or additionally, in another example, the first leg extendsin a first helical direction and the second leg extends in a secondhelical direction opposite the first helical direction.

Alternatively or additionally, in another example, the first and secondlegs of each of the repositioning and/or retrieval levers are attachedto an outside surface of the tubular body.

Alternatively or additionally, in another example, the first and secondlegs of each of the repositioning and/or retrieval levers are interwoventhrough the tubular body.

Alternatively or additionally, in another example, each of the first andsecond legs of each of the repositioning and/or retrieval levers isattached to an interwoven wire forming the tubular body at a pluralityof welds.

In another example, a braided stent includes a plurality of wiresinterwoven in a braided pattern to form a tubular stent body having alength between opposed atraumatic first and second open ends with eachopen end having a circumference. The braided stent further includes atleast three repositioning and/or retrieval levers attached to the stentbody at a plurality of discrete points. The repositioning and/orretrieval levers are spaced apart around the circumference of the firstopen end. Each repositioning and/or retrieval lever has a loop portionextending radially away from the tubular stent body and first and secondlegs extending along 25% or more of the length of the tubular stentbody.

Alternatively or additionally, in another example, the first and secondlegs extend helically along interwoven wires of the braided pattern ofthe tubular stent body.

Alternatively or additionally, in another example, the repositioningand/or retrieval levers are made of a material having a greaterstiffness than a material of the interwoven wires forming the tubularstent body.

Alternatively or additionally, in another example, the repositioningand/or retrieval levers extend radially outward from the tubular stentbody at an angle of between 30 and 90 degrees from a centrallongitudinal axis of the tubular stent body.

Alternatively or additionally, in another example, the repositioningand/or retrieval levers are configured to translate a radially inwardsqueezing force applied to the loop portion of the repositioning and/orretrieval levers at a location beyond the first open end to a radiallyinward contracting force along the first and second legs extending alongthe tubular stent body.

Another example is a method of radially collapsing a stent. The methodincludes applying a radially inward squeezing force to a plurality ofrepositioning and/or retrieval levers of a stent. The stent includes atubular body having a first open end and a second open end. Theplurality of repositioning and/or retrieval levers are spaced apartcircumferentially around the first open end and extend beyond the firstopen end. The tubular body is formed of one or more interwoven wires.Each repositioning and/or retrieval lever has first and second legsextending along a portion of the tubular body toward the second openend. The radially inward squeezing force is applied to the repositioningand/or retrieval levers at a location beyond the first open end, whichis translated to a radially inward contracting force along the first andsecond legs extending along the tubular body to radially contract thetubular body.

Alternatively or additionally, in another example, the plurality ofrepositioning and/or retrieval levers are made of a material having agreater stiffness than a material of the one or more interwoven wiresforming the tubular body.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present disclosure.The Figures, and Detailed Description, which follow, more particularlyexemplify some of these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. The drawingsillustrate generally, by way of example, but not by way of limitation,various embodiments discussed in the present document.

FIG. 1 is a partial expanded view of a stent of the prior art;

FIG. 2 is another view of the prior art stent of FIG. 1 being pulled bya retrieval device;

FIG. 3 is a perspective view of a hollow, tubular stent according to thepresent invention;

FIG. 4 is an expanded view of a wall portion of the stent of FIG. 3taken along line 4-4 showing a plurality of interwoven wires forming thetubular body of the stent;

FIG. 5 is a side view of one end of a braided stent with a closed-endloop design and retrieval and/or repositioning levers in accordance withan embodiment of the disclosure;

FIG. 6 is an end view of the stent of FIG. 5;

FIG. 7 is a side view of one end of a stent in accordance with anotherembodiment of the disclosure;

FIG. 8 is a side view of the stent end of FIG. 7 in a retracted orcompressed state for retrieval;

FIG. 9 is a side view of a portion of one end of a stent in accordancewith an embodiment of the disclosure;

FIG. 10 depicts a stent having a covering in accordance with anembodiment of the disclosure;

FIG. 11 is a cross-sectional view of the stent of FIG. 10 taken alongline A-A showing an outer covering surrounding the tubular body of thestent; and

FIG. 12 is an alternative cross-sectional view of the stent of FIG. 10taken along line A-A showing an inner covering disposed within thetubular body of the stent.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the terms “about” may include numbers thatare rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include one or more particular features,structures, and/or characteristics. However, such recitations do notnecessarily mean that all embodiments include the particular features,structures, and/or characteristics. Additionally, when particularfeatures, structures, and/or characteristics are described in connectionwith one embodiment, it should be understood that such features,structures, and/or characteristics may also be used connection withother embodiments whether or not explicitly described unless clearlystated to the contrary.

The following detailed description should be read with reference to thedrawings in which similar structures in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of thedisclosure.

FIG. 1 depicts a prior art stent 10 including a retrieval and/orrepositioning loop 12. The retrieval and/or repositioning loop 12includes two wires 14, 18 that are circumferentially disposed about theend 16 of stent 10. The two wires 14, 18 are configured to be graspedwith a retrieval device such as rat tooth forceps or hooking device andpulled axially to contract the end 16 of the stent 10. The two wires 14,18 cooperatively work in conjunction with each other to cinch the end 16of the stent 10 when pulled on by the retrieval device. Further detailsof this prior art stent 10 with its retrieval and/or repositioning loop12 may be found in U.S. Patent Application Publication No. 2006/0276887to Brady et al., the contents of which are incorporated herein byreference. Moreover, another retrieval and/or repositioning loop of astent is disclosed in U.S. Patent Application Publication No.2006/0190075 to Jordan et al., the contents of which are incorporatedherein by reference.

FIG. 2 shows the prior art stent 10 being pulled (P) by a retrievaldevice 300 in an axial direction away from the stent end 16. Theretrieval device 300 may hold both wires 14, 18 in a fixed position asit pulls the stent 10. The retrieval device 300 hinders the wires 14, 18from moving past each other which causes the stent end 16 to remain in aflared state and prevent the wires 14, 18 from fully cinching the stentend 16. Additionally, FIG. 2 shows that the stent 10 body is not fullyradially contracted due to the reduced ability of the wires 14, 18 toslide relative to each other.

Thus, there is a need for a retrieval and/or repositioning member thatprovides both improved stent end cinching and improved stent body radialcontraction. Further, there is a need for a retrieval and/orrepositioning member that is capable of cinching the end of the stentand radially contracting the stent body using a variety of devices usedby a practitioner. Furthermore, there is a need for a retrieval and/orrepositioning member that provides for substantially even radialcontraction of the stent end and stent body and permits easy access tothe retrieval and/or repositioning member by a practitioner.

The present disclosure provides a plurality of retrieval and/orrepositioning levers. The retrieval and/or repositioning levers areconfigured to radially contract the end of the stent and radiallycontract the stent body. Additionally, the retrieval and/orrepositioning levers may provide a structure which has the requiredtensile strength to prevent fracture or damage to the stent when forceis applied to reposition or retrieve the stent.

FIG. 3 depicts a stent 100. The stent 100 is a hollow tubular structurehaving opposed first and second open ends 105, 110 and defines a tubularwall 120 therebetween. A portion of the tubular wall 120 is depicted inFIG. 4 as having a plurality of elongate wires 115 formed into thetubular wall 120. The elongate wires 115 traverse the length of thestent 100 in a direction transverse to the longitudinal length of thestent 100. For example, the elongate wires 115 may extend along thelength of the stent 100 in a helical arrangement, with a portion of theelongate wires 115 extending in a first helical direction and a secondportion of the elongate wires 115 extending in a second helicaldirection, opposite the first helical direction. The elongate wires 115may be interwoven such that wires 115 extending in the first helicaldirection cross over and/or under wires 115 extending in the secondhelical direction at a plurality of cross-over points along the lengthof the stent 100. The wires 115 may traverse the length of the stent 100in a down-and-back fashion in which a middle portion of each wire 115forms a bend or loop 130 (see FIG. 5) and end portions on either side ofthe middle portion extend to the opposite end of the stent 100 and areinterwoven to form the tubular body of the stent 100. The elongate wires115 may be interwoven to form the tubular wall 120 by braiding the wires115, winding the wires 115, knitting the wires 115, and combinationsthereof. Preferably, the wires 115 are braided in a braided pattern 125to form the tubular wall 120. A useful non-limiting braided patternincludes a one over and one under pattern, but other patterns maysuitably be used.

As depicted in FIG. 5, the stent 100 is desirably an atraumatic stenthaving no sharp terminating members at one or both of the opposed firstand second open ends 105, 110. The elongate wires 115 terminating at thefirst open end 105 may be mated to form closed loops 130 and adjacentlymated wires may be secured to one another by mechanical means, such aswelds. The second open end 110 may also include closed loops formed bybending the wires 115 back such that the wires 115 re-enter the braidingpattern of the stent 100. Alternatively, the first open end 105 mayinclude closed loops formed by bending the wires 115 back such that thewires 115 re-enter the braiding pattern of the stent 100 and the secondopen end 110 may include the ends of the elongate wires 115 which aremated to form closed loops. The positioning of adjacently mated wires toform closed-loop end designs is further described in U.S. Pat. Nos.7,655,039, and 7,462,192, the contents of all which are incorporatedherein by reference.

The stent 100 may include multiple wires 115 of a metal material, suchas nitinol or nitinol-containing material, or other nickel-titaniumalloy, for example. In some instances, the wires 115 may have a diameterof about 0.011 inches, for example. The number of wires 115 and thediameters of the wires 115, which may be the same or different, depictedin FIG. 5 are not limiting, and other numbers of wires 115 and otherwire diameters may suitably be used. Desirably, an even number of wires115 may be used, for example, from about 10 to about 36 wires 115.

Desirably, the wires 115 are made from any suitable implantablematerial, including without limitation nitinol, stainless steel,cobalt-based alloy such as Elgiloy®, platinum, gold, titanium, tantalum,niobium, polymeric materials and combinations thereof. Useful andnonlimiting examples of polymeric stent materials includepoly(L-lactide) (PLLA), poly(D,L-lactide) (PLA), poly(glycolide) (PGA),poly(L-lactide-co-D,L-lactide) (PLLA/PLA), poly(L-lactide-co-glycolide)(PLLA/PGA), poly(D,L-lactide-co-glycolide) (PLA/PGA),poly(glycolide-co-trimethylene carbonate) (PGA/PTMC), polydioxanone(PDS), Polycaprolactone (PCL), polyhydroxybutyrate (PHBT),poly(phosphazene) poly(D,L-lactide-co-caprolactone) PLA/PCL),poly(glycolide-co-caprolactone) (PGA/PCL), poly(phosphate ester) and thelike. Wires made from polymeric materials may also include radiopaquematerials, such as metallic-based powders, particulates or pastes whichmay be incorporated into the polymeric material. For example theradiopaque material may be blended with the polymer composition fromwhich the polymeric wire is formed, and subsequently fashioned into thestent 100 as described herein. Alternatively, the radiopaque materialmay be applied to the surface of the metal or polymer wire 115 of thestent 100. In either embodiment, various radiopaque materials and theirsalts and derivatives may be used including, without limitation,bismuth, barium and its salts such as barium sulphate, tantalum,tungsten, gold, platinum and titanium, to name a few. Additional usefulradiopaque materials may be found in U.S. Pat. No. 6,626,936, thecontents of which are incorporated herein by reference. Metalliccomplexes useful as radiopaque materials are also contemplated. Thestent may be selectively made radiopaque at desired areas along the wireor may be fully radiopaque.

In some instances, the wires 115 may have a composite constructionhaving an inner core of tantalum, gold, platinum, tungsten, iridium orcombination thereof and an outer member or layer of nitinol to provide acomposite wire for improved radiopacity or visibility. In one example,the inner core may be platinum and the outer layer may be nitinol. Theinner core of platinum may represent about at least 10% of the wire 115based on the overall cross-sectional percentage. Moreover, nitinol thathas not been treated for shape memory such as by heating, shaping andcooling the nitinol at its martensitic and austenitic phases, is alsouseful as the outer layer. Further details of such composite wires maybe found in U.S. Pat. No. 7,101,392, the contents of which isincorporated herein by reference. The wires 115 may be made fromnitinol, or a composite wire having a central core of platinum and anouter layer of nitinol. Further, the filling weld material, if requiredby welding processes such as MIG, may also be made from nitinol,stainless steel, cobalt-based alloy such as Elgiloy, platinum, gold,titanium, tantalum, niobium, and combinations thereof.

One of the opposed open ends 105, 110 of the stent 100 may include twoor more retrieval and/or repositioning levers 140. It is noted that insome embodiments, both open ends 105, 110 of the stent 100 may includetwo or more retrieval and/or repositioning levers 140. The retrievaland/or repositioning levers 140 may be uniformly or non-uniformlyarranged around the circumference of the open end 105 and/or the openend 110 of the stent 100. In the device illustrated in FIG. 5, the firstopen end 105 includes three levers 140. The three levers 140 may beuniformly arranged around the circumference of the open end 105. Theretrieval and/or repositioning levers 140 may be useful forrepositioning and/or retrieval of an implanted or deployed stent 100.The retrieval and/or repositioning levers 140 allow a practitioner toradially contract and move, reposition and/or retrieve the stent 100within an implanted body lumen (not shown).

The stent retrieval and/or repositioning levers 140 may be made from abiocompatible material, such as a metallic or polymeric material. Thestent retrieval and/or repositioning levers 140 may be self-supporting,such that the stent retrieval and/or repositioning levers 140 may becantilevered and/or extend from the open end 105 of the stent 100 whileretaining their shape. In some instances, the stent retrieval and/orrepositioning levers 140 may be formed of a metal material, such as theabove described materials, including nitinol. The use of a metalmaterial, as compared to other conventional materials such as suturethread, has numerous advantages. For example, the self-supporting natureof the metal material may facilitate maintaining thelocation/orientation of the retrieval and/or repositioning lever 140.Furthermore, the metal material may permit radially compressive forcesapplied to the retrieval and/or repositioning levers 140 to betransferred through the retrieval and/or repositioning levers 140 toapply a corresponding radially compressive force to the tubular body ofthe stent 100 to aid in radially compressing the stent 100.

As depicted in FIG. 5 the stent 100 includes three retrieval and/orrepositioning levers 140. In other embodiments, the stent 100 may havetwo opposing levers, or four or more levers 140 evenly or unevenlyspaced around the circumference of the stent 100. For example, aplurality of levers 140 may be provided, generally spaced equally aroundthe circumference of the stent 100.

The retrieval and/or repositioning levers 140 may be formed of a wire148, for example, extending beyond the closed loops 130 at the end 105of the tubular body of the stent 100 and along the braid pattern 135forming the tubular body of the stent 100 for a portion of, or forsubstantially the entire length of the braided body portion of the stent100. For example, the retrieval and/or repositioning levers 140 may eachinclude a wire 140 forming two legs 142, 144 that extend beyond theclosed loops 130 at the end 105 of the tubular body of the stent 100 andalong the braid pattern 125 forming the tubular body of the stent 100.The apex 141 of the legs 142, 144 may be unitarily formed as a curvedloop or bend 141 of the wire 148 forming the legs 142, 144 of theretrieval and/or repositioning levers 140, while the bases 146 of eachof the legs 142, 144 which extend along body of the stent 100 may extendto an end of the wire 148 forming the legs 142, 144. The bases 146 ofeach of the legs 142, 144 may not be interconnected with one another.For example, the bases 146 of each of the legs 142, 144 may be spacedaway from one another throughout the tubular body of the stent 100.

The wire 140 forming the retrieval and/or repositioning lever 140 mayextend beyond the closed loops 130 at the end 105 of the tubular body ofthe stent 100 for a distance L. In some instances, distance L may be 5%to 50%, 10% to 50%, 10% to 30%, or 5% to 30% of the total stent bodylength, for example.

In some embodiments, the base 146 of each of the legs 142, 144 mayextend separately along the braided pattern 125 of the stent 100. Forexample, each of the legs 142, 144 may follow adjacent to and bejuxtaposed with a filament of the helical braid pattern extending in ahelical direction. For instance, the first leg 142 of the retrievaland/or repositioning lever 140 may extend in a first helical directionadjacent to a first filament of the braided pattern 125 and the secondleg 144 of the retrieval and/or repositioning lever 140 may extend in asecond helical direction, opposite the first helical direction, adjacentto a second filament of the braided pattern 125. The base 146 of thelegs 142, 144 may thus extend helically around the circumference of thestent 100 in some instances. Such a configuration may advantageouslyallow the retrieval and/or repositioning levers 140 to effectivelycircumscribe the circumferential perimeter of the stent 100, which mayfacilitate translation of the radially inward pinching or squeezingforce F1 to a radially compression force F2 along the length of thestent 100 along which the wires 148 are attached, as shown in FIG. 8. Inother embodiments, the base 146 of the legs 142, 144 may extend alongthe braided tubular body of the stent 100 substantially parallel to thelongitudinal axis of the stent 100.

The wire 148 forming the retrieval and/or repositioning lever 140 may beattached to the wires 115 forming the braided pattern 125 of the tubularbody of the stent 100 at a plurality of separate locations. Theattachment may be via weld, adhesive, wire wrapping, or any othersuitable attachment element or mechanism. In the embodiment illustratedin FIG. 7, the wire 148 is welded along an adjacently positioned wire115 of the braid pattern 125 of the stent 100 at multiple discrete weldlocations 150 along the wire 148. The wire 148 may be attached to theinside surface or outside surface of the stent 100. In some embodiments,the wire 148, after forming the loop or bend 141 and legs 142, 144 ofthe retrieval and/or repositioning lever 140, may enter into and/orfollow the normal braiding pattern 125 of the stent 100.

The loop or bend 141 may be bent radially outward from the circumferenceof the braided tubular body portion of the stent 100, as seen in FIGS.5-7 and 9. As shown in FIG. 8, when the loops 141 of each of theretrieval and/or repositioning levers 140 are accessed and squeezedradially together, the radially inward squeezing force F1 applied to thelevers 140 may be translated to a radially contracting force F2 alongthe braided tubular body of the stent 100, thereby radially contractingthe braided tubular body of the stent 100. The loop or bend region 141may also be referred to as a grabbing area or portion configured foreasy access by a practitioner, for example a practitioner using forceps(not shown) or other retrieval tool.

Further, as wires 148 forming the retrieval and/or repositioning levers140 are attached to the body of the braided stent 100, the wires 148forming the legs 142, 144 of the levers 140 extend along a length of thetubular stent body. The legs 142, 144 may extend along the entire orsubstantially the entire length of the tubular stent body to theopposite end, or partially along the tubular stent body. In someembodiments, the legs 142, 144 extend along 25% or more, 50% or more, or75% or more of the length of the tubular stent body, or any otherdistance along the tubular stent body. The retrieval and/orrepositioning levers 140 may provide a radially inward contractingaction along the longitudinal length of the stent 100 over which thewires 148 extend. The retrieval and/or repositioning levers 140 alsofacilitate pulling the stent 100 by providing a grasping region at theloops 141. Thus, the squeezing/pinching and pulling of the retrievaland/or repositioning levers 140 may provide for both radiallycontracting and pulling of the stent 100.

As depicted in FIGS. 5-7 the portion of the retrieval and/orrepositioning levers 140 extending beyond the tubular body portion ofthe stent 100 extend radially outward from the circumference of thetubular body portion of the stent 100. For example, the retrieval and/orrepositioning levers 140 may extend radially outward at an angle ofbetween about 20 degrees to about 90 degrees, between about 25 degreesto about 75 degrees, about 30 degrees to about 60 degrees, or about 45degrees to about 75 degrees from the longitudinal axis X of the stent100. The angle of the retrieval and/or repositioning levers 140 relativeto the axis X may be, for example, 25 degrees or more, 30 degrees ormore, 35 degrees or more, 40 degrees or more, 45 degrees or more, 50degrees or more, 55 degrees or more, 60 degrees or more, 65 degrees ormore, 70 degrees or more, 75 degrees or more, 80 degrees or more, or 85degrees or more degrees, or other desired angle. In the embodimentillustrated in FIG. 5, the retrieval and/or repositioning levers 140extend at an angle of about 30 degrees from the longitudinal axis X ofthe stent 100. In the embodiment illustrated in FIG. 7, the retrievaland/or repositioning levers 140 extend at an angle of about 70 degreesfrom the longitudinal axis X of the stent 100.

The wire 148 forming the retrieval and/or repositioning levers 140 mayhave the same or different properties than the wires 115 which form thebraided stent 100. For example, the wires 148 may be of the same ordifferent stiffness or flexibility, all of which may be tailored for aparticular application. In some embodiments, the wire 148 forming aretrieval and/or repositioning lever 140 may be stiffer than the stentwires 115 forming the braided pattern 125 of the tubular body of thestent 100. In some instances, the lever wire 148 may be formed of adifferent material and/or may have a different diameter than the stentwires 115. In some instances, the lever wire 148 may be stainless steelwhile the stent wires 115 may be formed of a nickel-titanium alloy, suchas nitinol. In some instances, the material forming the lever wires 148may have a stiffness greater than the material forming the wires 115 ofthe braided pattern 125 of the stent 100 and/or the material forming thelever wires 148 may have a modulus of elasticity (Young's modulus)greater than the material forming the wires 115 of the braided pattern125 of the stent 100. The choice of material, wire diameter andpre-treatment of the wires 148, 115 and stent configuration are some ofthe factors which may be varied to achieve particular stent properties.Additionally, as mentioned herein, the at least one retrieval and/orrepositioning lever 140 may also be made radiopaque by various methods,for example with a coating or finish, with a band or as part of thestent material, as further described herein. Color or different finishesmay also be added to the retrieval and/or repositioning lever 140 tovisually differentiate it from the rest of the stent wires 115.

In one embodiment, one end of the stent 100 may have weld joints 250attaching ends of two wires 115 of the stent 100 proximate one end ofthe braided tubular body of the stent 100. In these embodiments, theweld joint 250 may be positioned between the crossings of adjacent wires115, as shown in FIG. 9. In other embodiments, the weld joint 250 mayspan a crossing of adjacent wires 115. In FIG. 9, the opposing side ofthe stent is not shown for clarity. The wires 148 forming the retrievaland/or repositioning levers 140 may be welded to two ends of stent wires115 at a single weld 350 joining three wires (two ends of stent wires115 and lever wire 148), or the lever wire 148 may be joined to a singlestent wire 115 at a weld 150. In other embodiments, the stent weldjoints 250 joining ends of the wires 115 may be at the opposite end fromthe retrieval and/or repositioning levers 140, and the end of the stenthaving the retrieval and/or repositioning levers 140 may only includethe welds 150 joining the lever wires 148 to the stent wires 115.

As depicted in FIG. 10, in some embodiments the stent 100 may includinga covering 70 covering at least a portion of the braided tubular body ofthe stent 100. For example, the covering 70 may fully cover the entirelength of the braided tubular body of the stent 100, forming a fullycovered stent in which all of the interstices defined in the braidedpattern are covered with the covering 70 to prevent tissue in-growth, orthe covering 70 may cover only a portion of the length of the braidedtubular body of the stent 100, forming a partially covered stent inwhich a portion of the interstices defined in the braided pattern remainuncovered to permit tissue in-growth. The retrieval and/or repositioninglevers 140 may not be covered by the covering 70, thus remain uncovered.In some instances, the stent 100 may be dipped into a solution ofsilicone or other polymer to form the covering 70. In other instances, apolymer sheet or tube may be placed around the tubular body and/orwithin the tubular body to form the covering 70. The coating or coveringmay be a polymer covering, such as a polytetrafluoroethylene (PTFE) orsilicone covering, however other coverings, particularly elastomericpolymers, may be used. Non-limiting examples of useful polymericmaterials include polyesters, polypropylenes, polyethylenes,polyurethanes, polynaphthalenes, polytetrafluoroethylenes, expandedpolytetrafluoroethylene, silicone, and combinations and copolymersthereof.

The covering 70 may be disposed on external surfaces 72 of the tubularbody of the stent 100, as depicted in FIG. 11, or disposed on theinternal surfaces 74 of the tubular body of the stent 100, as depictedin FIG. 12, or on both the internal and external surfaces of the tubularbody of the stent 100, thereby embedding the stent 100 in the polymericmaterial. FIGS. 11 and 12 are alternative cross-sectional views takenalong line A-A of FIG. 10 looking toward the second end 110, without theretrieval and/or repositioning levers 140.

With any embodiment, the stent 100 may be used for a number of purposesincluding to maintain patency of a body lumen, such as in the coronaryor peripheral vasculature, esophagus, trachea, bronchi colon, biliarytract, urinary tract, prostate, brain, and the like. The devices of thepresent invention may also be used to support a weakened body lumen orto provide a fluid-tight conduit for a body lumen.

Also, the stent 100 may be treated with any known or useful bioactiveagent or drug including without limitation the following:anti-thrombogenic agents (such as heparin, heparin derivatives,urokinase, and PPack (dextrophenylalanine proline argininechloromethylketone); anti-proliferative agents (such as enoxaprin,angiopeptin, or monoclonal antibodies capable of blocking smooth musclecell proliferation, hirudin, and acetylsalicylic acid);anti-inflammatory agents (such as dexamethasone, prednisolone,corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine);antineoplastic/antiproliferative/anti-miotic agents (such as paclitaxel,5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones,endostatin, angiostatin and thymidine kinase inhibitors); anestheticagents (such as lidocaine, bupivacaine, and ropivacaine);anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGDpeptide-containing compound, heparin, antithrombin compounds, plateletreceptor antagonists, anti-thrombin antibodies, anti-platelet receptorantibodies, aspirin, prostaglandin inhibitors, platelet inhibitors andtick antiplatelet peptides); vascular cell growth promotors (such asgrowth factor inhibitors, growth factor receptor antagonists,transcriptional activators, and translational promotors); vascular cellgrowth inhibitors (such as growth factor inhibitors, growth factorreceptor antagonists, transcriptional repressors, translationalrepressors, replication inhibitors, inhibitory antibodies, antibodiesdirected against growth factors, bifunctional molecules consisting of agrowth factor and a cytotoxin, bifunctional molecules consisting of anantibody and a cytotoxin); cholesterol-lowering agents; vasodilatingagents; and agents which interfere with endogenous vasoactivemechanisms.

Further, with any embodiment of the stent 100 the general tubular shapemay be varied. For example, the tubular shape may have a varieddiameter, may be tapered, and may have one or more outwardly flared endsand the like. Further, the ends of the stent 100 may have a largerdiameter than the middle regions of the stent 100. In one particularlyuseful embodiment, at least one of the ends of the stent 100 maytransition from one diameter to a larger diameter forming a flared endregion. In some embodiments, both ends of the stent 100 may transitionin this manner to yield “flared” end regions at the ends of the stent100, as depicted in FIG. 10.

Various stent types and stent constructions may be employed for thestent 100. For example, the stent 100 may be a self-expanding stent or aballoon expandable stent. The stent 100 may be capable of radiallycontracting to a compressed or collapsed configuration for delivery, andthen expandable to an expanded configuration during deployment in thebody lumen. Thus, the stent 100 may be described as radially distensibleor deformable. Self-expanding stents include those that have aspring-like action which causes the stent to radially expand, or stentswhich expand due to the memory properties of the stent material for aparticular configuration at a certain temperature. The configuration ofthe stent may also be chosen from a host of geometries. For example,wire stents can be fastened into a continuous helical pattern, with orwithout a wave-like or zig-zag in the wire, to form a radiallydeformable stent. Individual rings or circular members can be linkedtogether such as by struts, sutures, welding or interlacing or lockingof the rings to form a tubular stent. In other embodiments, the stent100 may be formed as a monolithic tubular member by etching or cutting apattern of interconnected struts from a tube.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of thedisclosure. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

The invention claimed is:
 1. A braided stent comprising: a plurality ofwires interwoven in a braided pattern to form a tubular stent bodyhaving a length between opposed atraumatic first and second open endswith each open end having a circumference; at least three repositioningand/or retrieval levers attached to the stent body at a plurality ofdiscrete points, the repositioning and/or retrieval levers spaced apartaround the circumference of the first open end, each repositioningand/or retrieval lever formed from a single continuous wire having aloop portion extending radially away from the tubular stent body andfirst and second legs extending along 25% or more of the length of thetubular stent body, wherein the loop portion is positioned between thefirst and second legs.
 2. The braided stent of claim 1, wherein thefirst and second legs extend helically along interwoven wires of thebraided pattern of the tubular stent body.
 3. The braided stent of claim1, wherein the repositioning and/or retrieval levers are made of amaterial having a greater stiffness than a material of the interwovenwires forming the tubular stent body.
 4. The braided stent of claim 1,wherein the repositioning and/or retrieval levers extend radiallyoutward from the tubular stent body at an angle of between 30 and 90degrees from a central longitudinal axis of the tubular stent body. 5.The braided stent of claim 1, wherein the repositioning and/or retrievallevers are configured to translate a radially inward squeezing forceapplied to the loop portion of the repositioning and/or retrieval leversat a location beyond the first open end to a radially inward contractingforce along the first and second legs extending along the tubular stentbody.
 6. The braided stent of claim 1, wherein the first open end of thestent body is defined by a plurality of closed loops, wherein the loopportions of the repositioning and/or retrieval levers extendlongitudinally beyond the plurality of closed loops.
 7. The braidedstent of claim 1, wherein first and second terminal ends of the singlecontinuous wire are positioned between the first and second open ends ofthe tubular stent body.
 8. The braided stent of claim 1, wherein theplurality of repositioning and/or retrieval levers are separate elementsfrom the plurality of interwoven wires forming the stent body.
 9. Thebraided stent of claim 1, wherein the first and second legs of each ofthe repositioning and/or retrieval levers extend substantially over anentire length of the tubular body from the first open end to the secondopen end.
 10. The braided stent of claim 1, wherein each of the firstand second legs of each of the repositioning and/or retrieval leversextends helically along an interwoven wire of the plurality ofinterwoven wires forming the tubular body.
 11. The braided stent ofclaim 10, wherein the first leg extends in a first helical direction andthe second leg extends in a second helical direction opposite the firsthelical direction.
 12. The braided stent of claim 1, wherein the firstand second legs of each of the repositioning and/or retrieval levers areinterwoven through the tubular body.
 13. The braided stent of claim 1,wherein each of the first and second legs of each of the repositioningand/or retrieval levers is attached to an interwoven wire of theplurality of interwoven wires forming the tubular body at a plurality ofwelds.